1. Field of the Invention
The present invention relates to an image forming apparatus, and particularly to an improved contact assembly for a drum, such as a photosensitive drum, for the image forming apparatus. More particularly, the invention provides an improved grounding assembly for the photosensitive drum.
2. Discussion of the Background
U.S. Pat. Nos. 5,845,173 and 7,020,410 provide background information regarding the field of art of the invention, and thus these references are hereby incorporated by reference in their entirety.
An image forming apparatus, such as a printer, a photocopier, etc., includes a photosensitive member, typically in the form of a photosensitive drum. The performance of the photosensitive drum is of critical importance, since the image being produced (or reproduced) is formed and developed on the drum. The developed image is then transferred from the drum to, e.g., a sheet of paper. Typically, the drum is formed of metal such as aluminum, and the metal is anodized or coated to provide a thin dielectric layer. The drum is then coated with photogeneration and photoconduction layers over the dielectric layer.
In forming an image, an electrostatic image is formed on the drum, and that image is developed with a developing medium, such as toner. Since the image is formed electrostatically, it is extremely important that any undesired charges or built-up charges are removed, or grounded from the drum utilizing a grounding expedient. This grounding must occur despite the anodized or coated layers which can be disposed on the drum, and which act as insulators.
In a known grounding arrangement, a grounding plate is fastened to a flange which extends into one end of the photosensitive drum. The flange is secured in place, for example, with an adhesive. This grounding plate includes radial projections, which make contact with an inner surface of the photosensitive drum to provide an electrical grounding contact therewith.